I got OEM sprockets through munnracing.com and the DID ZVMX 525 chain from motorcyclesuperstore.com with a coupon code and that made it the lowest $$ I could find. I haven't had a coupon code for quite a while, maybe they stopped offering them? I kept the same 16/42 stock gearing but the 45t rear is actually cheaper then the 42t. I ordered the 120 link chain but should have ordered the 130 so I would have a section of chain after cutting it down to 118 links, for trail side repairs.

__________________
A mangy man chasing a cautionary tale
Lurking more and posting less

Hi, do yourself a favor and only use OEM front sprockets. I learnt the hard way as an aftermarket sprocket ate my splines. Nut was torqued up right so can only assume sprocket was too hard. Now have sprocket welded on

I use Stealth/Sidewinder/Krause Racing rears exclusively, the aluminum over steel. They last for years and years, and with the DID ZVM chain (best chain you can buy), I go years without adjusting chains, 5 tires at least on my Ducati without touching the adjusters, 2 years on my YZ450F without adjusting it, and I've got the same setup on my KTM950, been on there about 6 months or so, no adjustments at all, not even after breaking it in. And I always use stock countershaft sprockets. Its worked for me.

The set up has probably the most expensive chain you can buy, about $215, the sprockets are fairly cheap at $80,but to me, it's worth it. No issues, long life.

I have changed rears twice using the original nuts and bolts. I don't know of a reason to change nuts and bolts that do not appear to be damaged, but if someone else does, I am all ears.

the aftermarket industry sure sells a lot of sprocket bolt kits
The 950 doesnt fly much but a loose sprocket bolt can be catastrophic. I have about 4 changes on mine using blue locktitehttp://www.mechanicsupport.com/stop_nut.html

Quote:

Several aircraft accidents (Canadian TSB Report A97O0055) and aircraft control problems (C-130 aileron) caused by lock nuts coming loose have challenged the idea that lock nuts can be reused.

Air Force T.O. 1-1A-8 now states: "New self-locking nuts shall be used each time components are installed in critical areas throughout the aerospace vehicle" This seems a more practical policy given the low cost of a lock-nut.

__________________from a cloud of dust we race, then into the dust we return, across the finish line
04 KTM 950 S
04 KTM 525 EXC street plated

My old KTM 500MX would really beat the sp rocket bolts up, they were visibly worn at at each change, and wore out the holes so there was a lot of slop. I reamed the holes to the next bigger size, and made sure every thing fit tight. A rear hub for an oldbKTM dirt bike was about $500, so I didn't want to break the ears off it, that's why some people change them out every time. My 950 uses that strange pin setup, and 2 places told me not to replace the screw that go into the pins if they are not damaged.

If your sprocket rides directly on the screws, some do, some don't, I'd change them, they are cheap insurance.

Don't need to change my underwear often- I can keep using the same pair whenever I change my pants.

(OK, the comparison breaks down- but it's was a fun thing to say)

I always replace. The nuts are "pinched" to lock down, and once used will not provide the same grip on the bolt. Sure, one can use Loctite which will help, but I'd rather have the combinitation of the two.

I have seen the consequences of nut/bolt failure on a sprocket, and it's worth the several dollars to me when I replace a sprocket just for that extra-special respect for things mechanical.